PROJECT SUMMARY We have developed a novel and powerful mouse model for identifying the mechanisms of Neisseria asymptomatic colonization and persistence. It avoids the issue of host restriction that have greatly impeded the field. It allows us to study two processes that have been intractible to experimention, asymptomatic colonization and persistence. It allows us to identify and dissect mechanisms of Neisseria-host interactions from the standpoint of both host and bacterium. Using this unique model, we will identify immune processes and mouse genes that are critical for host susceptibility to Neisseria asymptomatic colonization/persistence, and bacterial genes that are critical for these processes.